cDNA and genomic clones for different types of collagens have been isolated and characterized. Type IV collagen is the main collagen of the lens capsule and is found in all basement membranes. A set of synthetic oligonucleotides (CCCATA/GAANCCT/CTC) was derived from the published amino acid sequence (Glu-Gly-Phe-Met-Gly) for alpha 1 Type IV collagen. This set of oligonucleotides was labelled with P32 and hybridized to the l00,000 colonies of a mouse cDNA library. One colony was isolated that had an insert coding for alpha 1 Type IV collagen. This colony (pCIV-1-225) codes for 270 amino acids from the helical portion of the Type IV collagen. There are four interruptions in the Gly-X-Y repeats. Northern analysis shows that the mRNA for the alpha 1 Type IV collagen is 7,400 bases long, suggesting that it contains a large untranslated region. With the help of the cDNA clone, we isolated genomic clones for the alpha 1 Type IV collagen from mouse, human, and chicken. The mouse genomic clone shows a gene structure that is as complex as the gene structure of alpha 2 Type I collagen gene from the chicken. Type I collagen cDNA clones for both chains (alpha 1 and alpha 2) from the mouse have been isolated and characterized. Type I collagen synthesis in the cornea will be studied with these molecular probes. Type II collagen cDNA clones and genomic clones from the chicken have been isolated and characterized. Type II collagen synthesis for the vitreous body will be analyzed. Sea urchin collagen clones related to the basement membrane collagen of the mouse have been isolated and are being characterized.